Stopping power is largely a myth. They didn't name names but I'm pretty sure the 17 year study they kept referring to was by Marshall & Sanow and they have been completely discredited. Even though their study is discredited the rounds they say are most effective do appear to be the most effective on the street. At least the two in the video did say shot placement is everything if you have a round with sufficient expansion and penetration. I have been a .40 S&W guy for years. My EDC gun was a Glock G23. I still think the .40 is an excellent cartridge and it's ballistics are on a par with the best .45 rounds. But with modern +P JHPs the difference between 9 mm, .40 S&W, and .45 ACP is not that much. Any of them will do the job if you put them where they need to go. In a big step for me I have gone to the 9 mm Kahr PM9 and a Glock G19 for carry guns. I still think the .40 and .45 are more powerful rounds I've just finally joined the majority who say the difference isn't that important. The picture below is self explanatory. The chart is something I did one night bored with nothing else to do. There does seem to be a relationship between kinetic energy and round effectiveness. Quantifying it will probably remain impossible because of the large number of contributing factors that cannot be controlled.
Speer Gold Dot JHP Muzzle Energy Descending Order
980 ft.lbs, 304 m, .44 Magnum 210 gr, 453 BEN
584 ft.lbs, 181 m, .357 Magnum 125 gr
535, ft.lbs, 195 m, .357 Magnum 158 gr
518 ft.lbs, 194 m, .45 ACP +P 200 gr
506 ft.lbs, 169 m, .357 SIG 125 gr
500 ft.lbs, 150 m, .327 FedMagnum 100 gr
496 ft.lbs, 186 m, .40 S&W 155 gr
488 ft.lbs, 185 m, .45 GAP 185 gr
484 ft.lbs, 190 m .40 S&W 165 gr
453 ft.lbs, 195 m, .45 ACP 185 gr
420 ft.lbs, 185 m, .40 S&W 180 gr
418 ft.lbs, 194 m .45 GAP 200 gr
410 ft.lbs, 148 m, 9mm Luger +P 124 gr
404 ft.lbs, 205 m, .45 ACP 230 gr
374 ft.lbs, 139 m, 9mm Luger 115 gr
364 9mm Luger 124 gr
340 .44 Special 200 gr
317 9mm Luger 147 gr
312 45 Colt 250 gr
248 .38 Special +P 125 gr
196 .390 Auto 90 gr
123 .32 Auto 60 gr
63 .25 Auto 35 gr
The second number is momentum in no recognized unit. It is useless for
comparing to anything not on the chart but accurate for displaying relative
momentum between the included rounds.